Java Hotspot Client VM
The Java HotSpot Client VM is the default virtual machine of the Java 2 SDK and Java 2 Runtime Environment. As its name implies, it is tuned for best performance when running applications in a client environment by reducing application start-up time and memory footprint.
Java Hotspot Server VM
The Java HotSpot Server VM is designed for maximum program execution speed for applications running in a server environment. The Java HotSpot Server VM is invoked by using the -server command-line option when launching an application, as in
Java -server myapp
Some Features of Java Hotspot Technology, Common To Both VM IMPLEMENTATIONS, ARE The FOLLOWING.
Adaptive compiler - Applications are launched using a standard interpreter, but the code is then analyzed as it runs to detect performance bottlenecks, or "hot spots" The Java HotSpot VMs compile those performance-critical portions of the code for a boost in performance,. while avoiding unnecessary compilation of seldom-used code (most of the program). The Java HotSpot VMs also usesthe adaptive compiler to decide, on the fly, how best to optimize compiled code with techniques such as in-lining. The runtime analysis performed by the compiler allows it to eliminate guesswork in determining which optimizations will yield the largest performance benefit Rapid memory allocation and garbage collection -. Java HotSpot technology provides for rapid memory allocation for objects, and it has a fast, efficient, state-of-the- Art Garbage Collector. Thread synchronization - The Java Programming Language Allows for use of multiple, control paths of program execution (Called "Threads"). Java Ho tSpot technology provides a thread-handling capability that is designed to scale readily for use in large, shared-memory multiprocessor servers.http: //wwws.sun.com/software/solaris/java/wp-hotspot/
